1. Field of the Invention
This invention relates to an epoxy resin composition capable of being rapidly cured by heating and providing a coated film having good adhesion and impact strength and excellent chemical resistance.
2. Description of the Prior Art
It is known to use an epoxy resin composition as a powder paint. The cured coated films obtained with conventional epoxy resin compositions have low adhesion, low impact strength and low flexural strength and their resistance to strong acids, strong alkalies and highly polar solvents is also low.
It is also known that a solvent-based phenol-epoxy resin paint, i.e., a paint obtained by dissolving a resole-type phenolic resin as a solution and a solid bisphenol A-type epoxy resin in a solvent and then mixing them, can be used as a lining or insulation varnish for tanks, drums and pipes used in handling foodstuffs in fields which require both chemical resistance and thermal stability. The mixture is baked at a high temperature to form a coated film while the solvent is volatilized. Volatilization of a large quantity of solvent occurs when this type of paint is used to form a film and this leads to environmental pollution. Furthermore, since a resole-type phenolic resin is normally liquid, this resin cannot be formed into a powder paint. An attempt has been made to produce a solid resole-type phenolic resin using special techniques and to prepare a powdery phenol-epoxy resin paint therefrom. However, the resulting paint is not entirely satisfactory for practical purposes because baking at 200.degree. C. for as long as 20 minutes is required.